Одного не могу понять - как эти белки не перерабатываются в ЖКТ и не теряют свои антигенные свойства. Может, они как-то "защищены"!?
Two reasons allow one to argue that production of an edible plant-derived papillomavirus vaccine is feasible. First, a number of different antigens was already produced in plants and their oral delivery led to the induction of a protective immune response (summarized in reference 7). Secondly, it has been demonstrated that papillomavirus capsid antigens are immunogenic when delivered orally (11, 36), most likely because they are recognized by the immune system due to their virus-like structure. While the majority of antigens in the intestine are ignored by the immune system, M cells located in the Peyer's patches selectively take up particulate antigens such as virus particles (30) and transport them from the intestine to underlying follicles. The activation of a mucosal immune response leads to the production of secretory immunoglobulin A (IgA) antibodies but also to serum IgG antibodies. A putative prerequisite for the induction of a mucosal immune response against viral capsid antigens by edible vaccines, however, is that the proteins are presented to the M cells in a particulate state. This requires that the capsid proteins be able to assemble into VLPs or capsomeres within the transgenic plants and that upon ingestion and passage through the low pH of the stomach, these particles remain intact. In general, it can be expected that the sturdy plant cell walls provide a protective environment for the expressed antigens. In addition, it has been recently demonstrated that the papillomavirus capsid antigens remain immunogenic after exposure to low pH through oral delivery...
...Here, we demonstrated as a first step that it is possible to produce HPV-16 L1-transgenic plants expressing the HPV-16 L1 protein in a form appropriate for immunization purposes. Although neither tobacco plants nor potato plants are ideal plants for oral application, they are widely employed for research and proof-of-concept studies, since they are easy to transform and to work with. However, recombinant cholera toxin B produced in potato tubers was stable upon cooking and preserved its biological activity (1). Another advantage of using potato tubers is that they are biologically active during storage, and expression of the transgene can be induced postharvest and/or in nonsprouting tubers, which provides a safe production system and prevents environmental exposure. Our observations from feeding transgenic tubers to mice indicate that the oral immunogenicity, although detectable, clearly needs further improvement; such improvement will be achieved by further enhancement of transgene expression. "
from the article "Production of Human Papillomavirus Type 16 Virus-Like Particles in Transgenic Plants" by Sophia Biemelt, Uwe Sonnewald, Petra Galmbacher, Lothar Willmitzer, and Martin M&uumuller
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